Electric motor control unit



2 Sheets-Sheet l INVENTOR. WZM

ATTORNEY Aug. 22, w. P. LEAR ELECTRIC MOTOR CONTROL UNIT Original Filed Dec. 28, 1940 Aug. 22, 1944. w R L AR 2,356,253

ELECTRIC MOTOR CONTROL UNIT Original Filed Dec. 28, 1940 2 Sheets-Sheet 2 INVENTOR.

ATTORNEY Patented Aug. 22, 1944 UNITED STATES PATENT OFFICE ELECTRIC MOTOR CONTROL UNIT William P. Lear, Piqua, Ohio, assignor, by mesne assignments, to Lear Avia, Inc., Piqua, Ohio, a corporation of Illinois iriginal application December 28, 1940, Serial No.

372,059. Divided and this application Septemher 9, 1942, Serial No. 457,693

7 Claims. (Cl. 172-38) in a receiving socket, which stably supports the This invention relates to electric motive drives, and more particularly to a self-contained electrical drive assembly that is readily mounted and demounted from an apparatus. The unitary electro-mechanicai drive unit of the invention is particularly applicable in remote motor control systems.

It is among the objects of the present invention to provide a novel motor drive assembly incorporating a motor and clutch that are readily electrically and mechanically mounted and demounted in an apparatus.

Another object of the present invention is to provide a novel control motordrive unit incorporating several circuit components, which unit is readily mounted in a stable mechanical 'relation, and its circuit components simultaneously connected in a predetermined manner to a control circuit.

Still another object of the present invention is to provide a novel motor drive construction that is readily mounted and demounted in relatively inaccessible locations in the apparatus utilizing the motor drive.

A further object of the present invention is to provide a novel plug-in motor comtruction which greatly simplifies the servicing and maintenance of the motor in the field.

A further object of the present invention is to provide an electric motor having a novel pronged plug-in construction for readily mounting it in stable operative position.

These and other objects. advantages and features of the inventionwill. appear in the following detailed description of. a specific embodiment thereof, illustrated in the accompanying drawings, in which: a

Fig. 1 is a diagrammatic illustration, in perspective, of a system incorporating the motor drive unit of the invention.

Fig. 2 is a front elevational -view or the motor drive unit mounted in the system of Fig. 1.

Fi 3 is a side elevational view of the motor drive unit mounted in the system.

Fig. 4 is a rear elevational view of the socket and electrical connections for the motor drive unit.

Fig. 5 is a side elevational view, partly in section, of the electric motor drive assembly.

Fig. 6 is an end view of the motor drive of 8- 5.

In accordance with the invention, the motor drive unit preferably comprises a reversible electrical motor, an electromagnetic clutch coupled thereto, and reduction gearing when required. forming a unitary mechanical drive assembly. The electrical portions of the drive assembly are connected to metallic prongs projecting from one side of the motor base. The drive assembly is mechanically mounted by the projecting prongs drive unit in service, and also electrically connects the electrical components of the motorclutch drive to the exterior control circuit. The present case is a division of my Patent No. 2,317,- 922 entitled Directional radio system," which issued April 27, 1943, and assigned to the same assignee as this case.

Fig. 1 illustrates the drive unit of the present invention assembled in an automatic radio directional system. The motor drive unit is herein used as a remote control drive in circuit with an electronic control circuit. A remote control unit it is under manual control for operating the directional radio system. Chassis unit It contains the radio and electrical control circuits that are responsive to radio signals and also the control drive unit which is indicated at 62. The directional radio system comprises a loop antenna indicated at 20 that is rotatably mounted within streamline housing 2| supported on base 22. The loop antenna assembly is arranged on the body I! of a vehicle, such as an aircraft. Appropriate circuits for effecting automatic radio directional operation of the system, including a local control circuit for operating the control motor drive unit 52, are disclosed in my Patent No. 2,308,521 entitled Automatic radio direction indicator," which issued January 19, 1943, and also assigned to the same assignee as this case. An indicator 15 is coupled to the directional system for remotely indicating the bearing position to which control drive unit 52 motivates loop antenna 20.

. pied to the variable radio frequency condenser bank within chassis unit it for correspondingly tuning the contained direction finder circuits. A

tuning meter 31, in circuit with the radio system, apprises the pilot of the optimum tuning conditions. The mode of circuit operation for the direction finder system is controlled by switch lever 38 of control head It. The gain level of the system is adjusted by knob 30. The electrical connections between control head it and chassis unit it comprise junction box 40 and electrical cables ll, 42.

Chassis unit it contains a removable metallic casing 43 and front panel U. A non-directional antenna 45 is connected to terminal 46 on unit 15. A master on-off switch ll for the direction finder system is arranged on panel 44, remotely from control head ID. The power supply for the system is conducted through cables 42 and 46 via junction box 40. The loop winding 20 is electrically connected to radio circuit unit l5 by a shielded cable 49 through junction box 40 and cable 42. Connection between cable 49 and the rotatable loop antenna is afforded through slip rings, not shown. A quadrantal error corrector unit 50 is coupled between the rotatable loop antenna 20 and mechanical shaft 51 which operates the loop.

Loop drive shaft 5| is directly coupled to the drive unit 52 by flexible shaft 53 and shaft 54 of an H-coupling unit 55. Drive 52 is mounted on panel 44 of chassis unit l5. Shaft 53 is removably coupled to motor drive unit 52 by nipple arrangement 56. Electrical cable 42 is removably coupled to socket 51 on panel 44 through multiple plug 58. Control head shaft 66 is removably coupled to panel 44 by coupling piece 56. Chassis unit I5 may accordingly be readily uncoupled both electrically and mechanically from the remainder of the direction finder system for greatly facilitating its maintenance and servicing in the field.

In accordance with the present invention the drive unit 52 is readily insertable and detachable from the control chassis l5, and is remote from the loop antenna 20 driven thereby. The motor is electrically. shielded by housing 43. The cable connections to the motor are short and direct, and wholly within unit 15. No motor circuit connections are required between control unit l5 and the remotely positioned driven loop 20, thereby avoiding interference, as for example with a magnetic compass, or with radio reception. Radiation of clicking and commutator noises is eliminated by such complete local shielding of the motor and its connections.

The loop antenna 20 is directly mechanically driven by drive unit 52 through flexible mechanical shafting 5i, 53 joined at H-coupling unit 55. Bearin indicator 25 is mechanically coupled to the mechanical loop drive system by flexible shaft 60 connected with shaft 5| of H-unit 55. Shafts 54 and 6! of H-unit 55 are connected by 1:1 gearing 62, 63. Indicator shaft 60 is accordingly positively related with motor drive shaft 53, following in phase with shaft 5! that controls the angular position of loop antenna 20. Pointer 64 of indicator 25 is directly geared to shaft 60 in the same ratio that the loop antenna 20 is geared to drive shaft 5|. The angular relation between loop antenna 20 and needle 64 is initially adjusted so that indicator 25 shows the proper azimuthal bearing positions of the loop. The quadrantal error corrector unit 50 automatically compensates the bearing indications for extraneous radio distortions, in a manner well known in the art.

A second indicator unit 55 contains radio bearing index 66. Index 66 i connected to H-coupling unit 55 through mechanical shaft 61 and connections 66, 69. The 360 quadrantal error corrector 50 provided between loop antenna 20 and the plurality of bearing indicators and motor drive unit 52 aiiords the accurate azimuthal bearing indications at a plurality of positions on the aircraft. The indicators are thus individually interchangeable or removable, without affecting the operation of the remaining indicators. Coupling nipples 69 of H-unit 55 permit the convenient addition of an indicator if only one has been installed. Furthermore, when remote motor drive unit 52 is dissembled for servicing, the several indicators, 25 and 65, remain in in-phase relation with the loop antenna 20 and corrector 56, and need not be tested or readjusted after the servicing.

A manual loop drive crank 10 is mechanically connected to indicator 25 and its drive shaft 60 through the connection H indicated in dotted lines. In the event that manual direction finding operation is indicated in flight, such as when the electric motor control unit 52 is disconnected or inoperative, direct drive of loop 20 and the associated radio indices 64 and 66 is effected through crank 16. Aural or visual null signal reception is then used with the system. Crank 10 is normally unclutched from connection H to prevent its rotation during automatic directional operation. An adjusting knob I2 is coupled to bearing scale 13 for displacing it from its indicated "zero" position whenever desired during navigation.

In accordance with the present invention, the control motor drive unit 52 is mounted for ready removal from chassis panel 44.' Figs. 2 and 3 show details of its construction. Motor control unit 52 comprises a reversible electric motor 15, an electromagnetic clutch unit 16 and a reduction gearing unit 11, forming a mechanically inter-connected integral device. Mechanical cable 53 is detachably connected thereto through fluted output shaft 16, being held in position by nipple 56 threaded onto threaded projecting tube 16. Metallic prongs 60 project from insulated base 6| at the end of motor 15, and engage with split metallic receptacle members 62 of socket 63. Socket 63 is attached to supporting frame 64 extending from panel 44.

The mounting of motor drive assembly unit 52 is secured merely by screws 65 extending through gear unit 17 and engaging with panel 44. The rear of drive assembly 52 is mechanically supported by the four projecting prongs engaged with socket 63. By loosening screws 65, unit 52 including integrally connected motor 15, clutch 16 and gearing 11, is slipped oil panel 44. The electrical connections to the motor 15 and clutch 16 are made through prongs 60 to electrical cable 6'! via socket 63 including its spring contact members 62 and connecting lugs 66, as shown in Figs. 3 and 4. Electrical cable 8! and socket 83 remain stationary within the chassis and with respect to internal supporting frame 64. The motor 15 and clutch 16 are accordingly readily electrically disconnected from the circuit when uncoupled in the manner herein set forth, and conversely are readily mounted in position in their predetermined circuital relation.

Figs. 5 and 6 show further details, in cr0sssection, of motor drive unit 52. The illustrated motor 15 is of the reversible direct current type such as used in the automatic direction finder circuit disclosed in Patent No. 2,308,521 referred to above. It is to be understood, however, that a diii'erent type electric motor, such as an alternating current one, may instead be used, and that the motor drive assembly of the invention may be applied to other uses. Motor 15 has a commutator 66 and brushes 69. Suitable electric connections are made between the several projecting prongs 66 and the brushes and field coils of the motor, and energizing winding of electromagnetic clutch 16. Such circuital arrangements for motor 15 and clutch 76 are shown in my Patent No. 2,308,521, and in my Patent No. 2,267,114 of December 23, 1941, entitled Electypical electrical tromagnetic clutch. The

cable connections to the motor and clutch components therein shown are replaced by the prongs 80 of the present invention. Prongs 80 afford the electrical connection for motor 15 and clutch T6 with the electrical control circuits therefor, via cable 81. The prongs 80 also afford mechanical support for the motor drive assembly 52, in the manner hereinbefore described, particularly in connection with Figs. 2 and 3.

The electromagnetic clutch 16 may be of any desired construction; the illustrated arrangement corresponding to that shown in my Patent No. 2,267,114. The clutch 16 comprises a winding 90 which generates magnetic fiux through drive disk SI and driven disk 92 about a non-magnetic region 93. Abrupt starting and stopping of the low inertia driven disk 92 is effected by such arrangement, resulting in accurate positioning control by the motor drive unit. The ready mechanical and electrical mounting and demounting feature of the motor drive unit of the invention greatly enhances its usefulness in service. The projecting prongs 80 of the motor drive unit 52 preferably are mechanically designed and so arranged with respect to the receiving socket and receptacles 82 as to predetermine their engagement and insure the correct circuital connection of the drive unit with the control circuits. Such predetermined engagement is effected as by eccentric spacing of the prongs 80 and associated receptacles 82 or by having prongs of different diameters, or both.

Although a preferred arrangement of the invention has been described and illustrated, it is of course subject to variation and modification in practice as will be understood by those skilled in the art. It accordingly is not intended to limit the spirit and scopev of the invention, except as set forth in the following claims.

What I claim is:

1. An electric motor control unit comprising a body for the motor containing the field windings thereof, an armature rotatably supported within said body in cooperative relation with said field windings, prongs projecting from said motor body, said prongs being electrically connected to said field windings and armature in a predetermined relation, and a socket containing individual conducting spring elements for removably engaging said prongs to mechanically support the motor control unit and properly connect it to a control circuit.

2. An electric motor control unit comprising a body for the motor containing the stator thereof, a rotor rotatably supported within said stator in cooperative relation with said stator, an electromagnetic clutch secured to one end of said motor body and coupled to said rotor, a plurality of prongs projecting from the opposite end of said motor body, said prongs being electrically connected to the circuit components of the motor and clutch in a predetermined relation, whereby the motor unit is mechanically supported in position by plugging of said prongs into a socket and thereby simultaneously placed in proper electrical circuital relation with a control circuit.

3. An electric motor control unit comprising a body for the motor containing the field windings thereof. a rotor rotatably supported within said body in cooperative relation with said field windings, an electromagnetic clutch coupled to said rotor, a plurality of metallic members projecting from said motor body and being insulated therefrom, said members being electrically connected to said field windings and clutch in a predetermined relation, and a socket containing individual conducting receptacles for removably engaging said members to mechanically support the motor control unit and properly connect it to a control circuit.

4. An electric motor control unit comprising a body for the motor containing reversible field windings, an armature rotatably supported Within said body in cooperative relation with said field windings, an electromagnetic clutch secured to one end of said motor body and coupled to said armature, a plurality of prongs projecting from the opposite end of said motor body and being insulated therefrom, said prongs being electrically connected to said field windings, armature and clutch in a predetermined relation, whereby the motor unit is mechanically supported in position by plugging of said prongs into a socket and thereby simultaneously placed in proper electrical circuital relation with a control circuit.

5. An electric motor control unit comprising a body for the motor containing the stator thereof, a rotor rotatably supported within said body, an electromagnetic clutch secured to said motor body and coupled to said rotor. a plurality of prongs projecting from said motor body, said prongs being electrically connected to the circuit components of the motor and clutch in a predetermined relation, whereby the motor unit is mechanically supported in position by plugging of said prongs into a socket and thereby simultaneously placed in proper electrical circuital relation with a control circuit, and a coupling piece for detachably connecting a shaft to the output of said clutch.

6. An electric motor drive unit comprising a body for the motor containing the field windings thereof, a reduction gearing unit secured to said body, a rotor rotatably supported within said body in cooperative relation with said field windings, an electromagnetic clutch having a driving member coupled to said rotor and a driven member coupled to said reduction gearing, a plurality of metallic members projecting from said motor body and being insulated therefrom, said members being electrically connected to said field windings, rotor and clutch in a predetermined relation, and a socket containing individual conducting receptacles for removably engaging said members to mechanicall support the motor driving unit and properly connect it to a control circuit.

7. An electric motor drive unit comprising a body for the motor containing the field windings thereof, a reduction gearing unit secured to one end of said body, a rotor rotatably supported within said body in cooperative relation with said field windings, an electromagnetic clutch having a driving member coupled to said rotor and a driven member coupled to said reduction gearing, a plurality of metallic members projecting from the other end of said motor body and .being insulated therefrom, said members being electrically connected to said field windings, rotor and clutch in a predetermined relation, a socket containing individual conducting receptacles for removably engaging said members to mechanically support the motor driving unit at such other end and properly connect it to a control circuit, and fastening means for securing the reduction gearing unit to a support to mechanically support the motor driving unit at such one end thereof.

WILLIAM P. LEAR. 

